Drop on demand ink jet technology for producing printed media has been employed in commercial products such as printers, plotters, and facsimile machines. Generally, an ink jet image is formed by selective placement on a receiver surface of ink drops emitted by a plurality of drop generators implemented in a printhead or a printhead assembly. For example, the printhead assembly and the receiver surface are caused to move relative to each other, and drop generators are controlled to emit drops at appropriate times, for example, by an appropriate controller. The receiver surface may be a transfer surface or a print medium such as paper. In the case of a transfer surface, the image printed thereon is subsequently transferred to an output print medium such as paper.
FIG. 1 is a schematic view of a typical prior art drop generator 100 that may be incorporated into a printhead. Ink is supplied to an ink chamber 104 of the drop generator from a reservoir 108. A driver mechanism 110 is used to displace the ink in the ink chamber 104. The driver mechanism 110 typically consists of an actuator, or transducer, such as a piezoelectric material bonded to a thin diaphragm 114. When a voltage from a signal source 118 is applied to the driver mechanism 110, the piezoelectric material deforms and causes the diaphragm 114 to deflect and displace ink in the ink chamber resulting in the emission of ink drops from the nozzle 120. A plurality of drop generators may be provided in a printhead. Thickness uniformity of the piezoelectric actuators of a printhead is important to achieve uniform operating voltage, drop mass, and frequency response from each drop generator in the print head.
A commonly used piezoelectric material is a lead-based dielectric material having a good piezoelectric characteristic such as lead zirconate titanate (“PZT”). Piezoelectric materials are generally defined as being either thin-film elements having a thickness of up to approximately 10 μm, or thick-film elements having a thickness from about 10 μm to about 100 μm. The actuation force that may be generated by a piezoelectric element is generally proportional to the thickness of the element. Therefore, piezoelectric thick films have been generally been selected for use as actuators because they generate a larger actuation force than thin films.
Piezoelectric actuators having a thickness in the range of about 10 μm to 100 μm are not now able to be produced in high volume with economical yields which permit commercialization. For example, one previously known method for fabricating piezoelectric thick films comprises adhering a piezoelectric tile having a thickness greater than 100 μm to a flexible carrier and lapping the tile down to the required thickness. Lapping the piezoelectric tile on a flexible carrier, however, may result in a tile having thickness variations greater than +−5 μm. Another previously known method of fabricating piezoelectric thick films comprises screen printing. Screen printed films, however, typically undergo a heating step at about 1100 to 1350 degrees C. which may result in films having a lower piezoelectric constant than non-screen printed films.